[m6pwr]

BMW (p. 2 in the Service & Warranty handbook) says we 335d drivers should use ultra low sulphur diesel (ulsd) with a cetane number of 51 or greater. Cetane is the readiness of the diesel fuel to combust under compression. The higher the cetane number, the more power and smoothness of engine ops.

The content of ulsd is regulated by the U.S. EPA which says the fuel must meet the standards incorporated in ASTM D975. D975 (which addresses other things besides sulphur content - - like detergency, lubricity, and cetane) unfortunately is the lowest common denominator. It requires a min. cetane of only 40 or above.

Talking with folks at the fuel tech line at the Chevron refinery in CA, I told the man that BMW says I should use a diesel fuel with cetane number of 51 or above. This elicits guffaws and gales of laughter (hey Joe, this guy wants diesel with cetane of 51, bwaaahahaha!). The man says that's eurodiesel (premium diesel if you've ever fueled-up over there) and you can't get it anywhere in the US. He says Chevron is 46-48.

So, any of you 335d drivers using a fuel treatment - - something like Kleen Diesel - http://www.powerservice.com/dk/?

Better yet, anyone know of a diesel brand that reliably delivers cetane number 51 or above?

[Thud]

I use Chevron, it's fine.

I mean if you're going to be racing your car, you'd want to use race fuel (just like gas cars would), which is Syndiesel that has 60+ cetane.

[m6pwr]

Dynamite!! Where can you get this Syndiesel stuff?

[hotrod182]

Chevron is good. And Motorcraft Cetane Booster is good. One bottle treats many many gallons.

[Thud]

Originally Posted by m6pwr

Dynamite!! Where can you get this Syndiesel stuff?

Online (google it).
However, being a race fuel, it's not cheap.

It's also good as emergency fuel for the zombie apocalypse, because it'll last at least 10 years in storage.

[cssnms]

I just tried Power Service Diesel Kleen with Cetane Boost for the first time yesterday during my fill-up at Shell, which I believe in my area has a cetane rating of 45 or 46. So far I've noticed my engine is quieter and feels like it runs smoother.

Spicer did a test on the various diesel fuel treatments and the results were enlightening esp as they relate to the more populer and expensive products like "Stanadyne."

Diesel Fuel Additive Test

http://www.diesel**********/forum/sh...d.php?t=177728

Also no brand "reliably" carries high cetane, it depends on the supplier OR if you can locate a station in your area that carries "premium" diesel. If it's premium it will be labled as such along with the cetane lable to support it. Many BP stations carry premium diesel with 47 to 50 cetane. Otherwise, I tend to stick with the brand name stations since I believe their fuels are better quality and likely provide better lubricity. I also think the off-brand stations more often than not carry diesel fuels with lower cetane e.g. 40.

Here's a list of stations put together by someone on the TDI forum. The list is not to suggest that every station of the same brand carries the same cetane rated fuel, but it gives you a good idea of who might carry what. http://forums.tdiclub.com/showthread.php?t=200694

Here is a User maintained/updated Premium Diesel Fuel Map that you might find useful. The creator lives on the east coast so there is a bit of a focus on the east coast, but if you come across a station selling "premium" diesel e-mail him and he will add the station.

http://maps.google.com/maps/ms?ie=UT...21c64471c7&z=6

[Thud]

Doesn't BMW frown upon using any sort of diesel additive?

[maswastage]

Originally Posted by Thud

Doesn't BMW frown upon using any sort of diesel additive?

I believe the manual suggests not using any fuel additives. But then the manual also suggests using 51 cetane or higher ("premium diesel") which is not available in the US).

I've been using Diesel Kleen for the life of my car, almost 34,000 miles now, and I have no ill effects to report. I've actually never tried running the car without it so I don't know if there are any noticeable effects of running one or the other. That said, I do think there are long term benefits to running a fuel additive, if only because it boosts the cetane to the factory recommended specs, and Diesel Kleen has had pretty rave reviews everywhere I've looked.

[cssnms]

Originally Posted by Thud

Doesn't BMW frown upon using any sort of diesel additive?

Yes, but all car manufacturers frown upon fuel treatments. My Lexus owner's manual says the same thing, as did my Acura, but it doesn't keep me from using Techron in my Lexus. Manufacturers are not going to support and possibly provide warranty repairs that my ensue from the use of a product they don't sell and or have not tested. Otherwise, I think you would have people dumping all kinds of crap in their tanks. This is just my opinion though.

The Spicer test above is very informative. Check it out if you have not.

[Chriztofor]

Between adding diesel exhaust fluid and fuel additive to get the cetane levels higher seems like a pain in the butt, but if you love the car it probably doesn't matter. Not hating, just my 2 cents.

[cssnms]

Originally Posted by Chriztofor

Between adding diesel exhaust fluid and fuel additive to get the cetane levels higher seems like a pain in the butt, but if you love the car it probably doesn't matter. Not hating, just my 2 cents.

Dealer takes care of changing the DEF fluid during the oil change ( every 12k to 15k mi) which amounts to once a year, so not a big deal and it's easy enough to top off yourself once a year. As for the fuel treatment, nobody needs or is required to add a fuel treatment, that's personal perference, not unlike adding Techron to your gas tank every once in a while to keep injectors clean.

[Chriztofor]

Originally Posted by cssnms

Dealer takes care of changing the DEF fluid during the oil change ( every 12k to 15k mi) which amounts to once a year, so not a big deal and it's easy enough to top off yourself once a year. As for the fuel treatment, nobody needs or is required to add a fuel treatment, that's personal perference, not unlike adding Techron to your gas tank every once in a while to keep injectors clean.

Hey, someone is reading my posts. I thought I was talking to myself. . I don't like adding techron fuel injector cleaner. I have no choice. I prefer that there would be a serviceable fuel filter like the one on an e46, instead of being attached to the fuel sender unit that costs about $200 to replace. I do get your point though.

[m6pwr]

Thanks to all above - - some very informative posts and just the kind of feedback I'm looking for.